20890 Mercury NUT, ADJUSTING SCREW

Parts Needed
1 Make two plates (1) from 20 mm (.79") thick steel to the dimensions shown. Make hole (A) to the dimensions shown. 2 Make two plates (2) from 30.0 mm (1.18") thick steel to the dimensions shown. Make a 20 mm (.79") x 45° chamfer along sides (B) and (C) of one plate. Make a 20 mm (.79") x 45° chamfer along sides (D) and (E) of the other plate. 3 Make plates (3) and (4) from 20.0 mm (.79") thick steel to the dimensions shown. Make a 30° chamfer along end (A) of each plate. Make a 45° chamfer along end (B) of each plate. Use plate (3) for right side of machine and plate (4) for the left side of machine. 4 Make two plates (5) from 12.0 mm (.5") thick steel to the dimensions shown. These plates will not be needed if the bottom surface of the rail section is not cracked; see step 8, page 7.Reinforcement Plate Installation
1 Remove the rear axle from the machine; see the Service Manual. Disconnect and remove transmission pump suction hose (1) and brake pressure hose (2). This will give access for the welding procedure. 2 Put a fire-proof blanket over transmission oil cooler tubes (3) to prevent damage to the tubes from hot weld particles. 3 Inspect the frame rails at the rear of steering cylinder brackets (4) and at engine support (5). If there are any cracks, use an Arcair torch or similar tool to gouge (cut out) the crack. If the crack is through the frame side plates, remove the crack to the dimension shown. There must be a minimum gap of 6.0 mm (.25") at the root of the V. This will give access to put back-up strip (6) inside the frame rail as shown. Fill the V-groove with weld.4 If only the weld is cracked, remove the weld; no back-up strip is necessary. Gouge out all previous weld around the crack. Fill the crack with weld and grind the area smooth. Grind the frame rail smooth, and remove the weld tails from the steering cylinder bracket. 5 Tack weld plate (7) (item 1, page 2) in position on the outside of the frame rail as shown. Make a 10.0 mm (.38") fillet weld around the inside of hole (A) and all around the outside of the plate. Make a 20.0 mm (.79") bevel groove weld along the front end of the plate from (B) to (C). Grind the toe of the weld smooth at location (C).6 Tack weld plate (8) (item 2, page 2) with the chamfered side up, to steering cylinder bracket (4) and plate (7). Make a 10.0 mm (.38") fillet weld along the bottom of plate (8); do not weld around the radius at (F). Make a 20.0 mm (.79") flate V-weld along the top of plate (8) but do not weld around the radius at (F). Do not weld across the ends of plate (8). 7 Use a cutting torch to remove enough of gussets (9) and (10) [approximately 50.0 mm (2.0")] so reinforcement plate (11) (items 3 and 4, page 3) will fit above the bottom of the frame rail at (G). Cut the end of gusset (10) at an angle to fit tightly against plate (11). Grind the side of the frame smooth and remove the paint. Tack weld plate (11) in position. Make a 10.0 mm (.38") fillet weld along each side of plate (11). Make 20.0 mm (.80") bevel groove welds at locations (H) and (J) at the ends of plate (11). Make 10.0 mm (.38") fillet welds along each side of gussets (9) and (10).8 Inspect the bottom of the frame rail for cracks. If cracks are present make reinforcement plate (12) (item 5, page 3). Use an Arcair torch or a similar tool to gouge out the crack. Fill the crack with weld. Tack weld reinforcement plate (12) in position as shown. Make 10.0 mm (.38") fillet welds along each side of plate (12). Extend the welds 40.0 mm (1.5") beyond each end of plate (12). Do not weld along the ends of the plate. 7 Put paint on all the new welds and reinforcement plates. Install the parts that were removed in steps 1 and 2 on page 4. Be sure that the hoses do not touch the new reinforcement plates during full stop-to-stop oscillation of the rear axle. Be sure that brake hose (13) does not touch plate (11). If the hose does touch plate (11) it may be necessary to move clamp (14) so the hose does not touch the plate.